Samuel, a brilliant general and good politician, has managed to turn the fortunes to the Bulgarians.
In 986, Basil II leads thirty thouand soldiers in a campaign against Bulgaria.
The commanders of the eastern armies do not take part in the campaign because they are fighting with the Arabs.
The imperial army marches from Odrin via Plovdiv to reach Sredets (Sofia).
According to Leo Diaconus, the objective of their Emperor was to subdue the Bulgarians with one strike.
After the capture of Serdica, which is a strategic fortress between the northeastern and southwestern Bulgarian lands, Basil intends to continue his campaign towards Samuel's main strongholds in Macedonia.
On his way to Serdica (the Byzantine name of Sredetz, today Sofia, the capital city of modern day Bulgaria), Basil leaves a strong company under Leon Melissenos to guard the rear of his army.
When he finally reaches the walls of the city, Basil builds a fortified camp and besieges the fortress.
The siege lasts for twenty days of fruitless assaults, until shortage of food occurs in the imperial army.
Their attempts to find provisions in the surrounding country are stopped by the Bulgarians, who burn crops and even take the cattle of the Greek forces.
In the end, the city garrison breaks out of the walls, killing many enemy soldiers and burning all of the siege equipment, which the inexperienced imperial generals had placed too close to the city walls.
As a result of the successful Bulgarian actions, the imperial forces are no longer capable of taking the city with a direct assault.
They also cannot exhaust the defenders with hunger because, after their supplies are cut, the Greeks themselves have to deal with this problem.
In addition, an army led by Samuel marches into the mountains at the Greeks’ rear.
In the meantime, instead of securing the way for retreat, Leon Melissenos pulls back to Plovdiv.
This action is an additional reason for Basil to lift the siege.
The commander of the Western armies, Kontostephanos, persuades him that Melissenos had set off to Constantinople to take his throne.
